At 12 weeks post-commencement of treatment (Day 85), if a patient's disease status is classed as progressive disease (but without rapid clinical deterioration) the patient may remain on the trial for a further 6 weeks, when his/her disease status will be confirmed prior to the scheduled treatment. If disease progression is confirmed, the patient will cease treatment but will remain on the study and be observed for efficacy and safety until initiation of treatment with non-CVA21 anticancer therapies. However, survival will be followed until death. If stable disease or better (CR or PR) is observed at this time, the patient will continue treatment as per the protocol. Complete and partial responses will be confirmed at the next contrast-enhanced CT or MRI scan analysis.